1. Field of the Invention
The present invention relates to a pneumatic operator for a molded case circuit breaker, switches and the like and, more particularly, to a pneumatic operator having a reciprocally mounted actuator, adapted to be coupled to a circuit breaker operating handle, for moving the operating handle to an open position or, alternatively, to a closed position, which may be controlled from a remote location.
2. Description of the Prior Art
Molded case circuit breakers are generally used to provide overcurrent protection for various types of electrical equipment. However, in some applications, it is desirable to have a motor operator for the circuit breaker. Such motor operators make it easier to operate large circuit breakers and make remote operation of the circuit breaker possible. Such a remote control system is also useful for molded case switches. In such applications, electric operators have been provided that are adapted to be mechanically coupled to the operating handle of the circuit breaker or molded case switch. Both solenoid operators and motor operators are known. Examples of solenoid operators for molded case circuit breakers and switches are disclosed in U.S. Pat. Nos. 4,553,115 and 4,642,726, assigned to the same assignee as the present invention. However, such solenoid operators are generally slow acting. Motor operators, on the other hand, are generally provided with high speed electric motors that are comparatively faster acting than a solenoid operator. An example of a motor operator is disclosed in U.S. Pat. Nos. 4,990,873, and 5,196,658 assigned to the same assignee as the present invention.
Both solenoid operators and motor operators are adapted to be rigidly mounted relative to the circuit breaker or molded case switch to be in communication with the operating handle. Such operators may either be disposed within the circuit breaker or switch housing or mounted either on the side or in the front of the circuit breaker. Examples of solenoid operators for molded case circuit breakers are disclosed in U.S. Pat. Nos. 4,553,115 and 4,642,726. An example of a motor operator is disclosed in U.S. Pat. No. 4,990,873.
Electric operators require an energy source to function. The electric operator, however, must include means for manual operation. This requirement for manual operation, promulgated in Underwriter's Laboratories Standard No. UL 489, is to allow for manual operation of the circuit breaker in the event of loss of electric power to the electric operator. Electric operators may fail if operated frequently within a short period of time, or if breaker begins to act differently due to wear. Electric operators also require multiple parts, e.g., the parts in the electric motor as well the coupling to the circuit breaker, all of which are subject to wear.
Pneumatic operators have been used as remote operators for circuit breakers, see e.g. U.S. Pat. No. 3,930,134. These pneumatic operators, however, were not coupled to molded case circuit breakers having an exposed operating handle and did not include a manual control means.
Therefore there is a need for a mechanical operator for a molded case circuit breaker which uses fewer parts than an electric operator.
There is further need for a mechanical operator for a molded case circuit breaker that is not dependent on a remote source of energy.